1. Field of the Invention
The present invention relates to an endoscope for bending and operating a bending portion provided at an insertion portion with a bending portion operation apparatus provided at an operation portion.
2. Description of the Related Art
In recent years, endoscopes capable of making observations or providing various therapeutic treatments by inserting an elongated insertion portion into a body have been utilized in a medical field. A bending portion which is configured, for example, to bend in upward, downward, leftward, and rightward directions is provided on an insertion portion distal end side of an endoscope having a flexible insertion portion.
The bending portion is configured to bend in the upward, downward, leftward, and rightward directions by, for example, pivotably linking a plurality of bending pieces. Bending wires that are pulling members whose distal ends are fixed to the bending pieces constituting the bending portion are inserted in and extend through the insertion portion. A bending portion operation apparatus for pulling the bending wires is provided at an operation portion located at a proximal end of the insertion portion. The bending portion operation apparatus includes, for example, a pulley, and proximal ends of the bending wires are fixed to the pulley.
According to the configuration, the bending portion is operated to bend in a surgeon's intended direction by the surgeon who operates the bending portion operation apparatus with fingers of one hand grasping the operation portion and pulling a desired one of the bending wires. As a result, the surgeon can easily perform, for example, insertion of the insertion portion of the endoscope into a site to be examined. The surgeon also can easily perform observation by directing an observation optical system disposed at a distal end portion of the insertion portion toward a target direction.
Examples of the bending portion operation apparatus that bends the bending portion in the upward, downward, leftward, and rightward directions include one in which an upward and downward bending operation knob (hereinafter abbreviated as an upward and downward knob) and a leftward and rightward bending operation knob (hereinafter abbreviated as a leftward and rightward knob) are stacked on one side surface of an operation portion, as illustrated in Japanese Patent Application Laid-Open Publication No. 2005-245545 (hereinafter referred to as Literature 1) and one in which a finger rest portion of an upward and downward bending operation lever (hereinafter abbreviated as an upward and downward lever) and a finger rest portion of a leftward and rightward bending operation lever (hereinafter abbreviated as a leftward and rightward lever) are provided on left and right sides in an upper surface side region of an operation portion, as illustrated in Japanese Patent Application Laid-Open Publication No. 2005-160791 (hereinafter referred to as Literature 2).
In the endoscope in Literature 1, a surgeon appropriately selects the upward and downward knob or the leftward and rightward knob and rotates the knob clockwise or counterclockwise by a desired amount. With the rotation, a bending wire is directly pulled, and a bending portion bends at a desired angle in a desired direction.
In the endoscope in Literature 2, a surgeon appropriately selects the finger rest portion of the upward and downward lever or the finger rest portion of the leftward and rightward lever and inclines the finger rest portion in an operation portion distal end direction or an operation portion proximal end direction by a desired amount. The inclination causes a bending wire to be directly pulled and a bending portion to bend at a desired angle in a desired direction.
Note that the endoscopes in Literatures 1 and 2 are so-called manually bending endoscopes which directly pull a bending wire. An electrically bending endoscope is illustrated in, for example, Japanese Patent Application Laid-Open Publication No. 2007-222671. In the electrically bending endoscope, a surgeon tilts and operates a bending operation input unit, such as a joystick. With the operation, a bending wire is pulled by driving force of a motor, and a bending portion can be bent as instructed through the tilt of the joystick. As a result, the surgeon is liberated from direct pulling of a bending wire.